High-rise apartment buildings often have balconies surrounded by glass barriers. Though a building may employ rooftop-anchored window washers to clean such exterior glass, such a service is costly, and typically only occurs a few times a year.
If an individual tenant wishes to clean the glass surrounding their own balcony at any other time, it is typically their own responsibility to do so. It would generally be too costly to hire a roof-top-anchored window washer to wash the glass for a single unit, so contractors or tenants typically just lean over the edge of the balcony to clean the glass manually, which poses a severe fall risk.
Besides being dangerous or fatal, leaning over to wash the glass of a single unit also typically results in significant amounts of dirty or soapy water soiling the glass of balconies situated below the balcony being washed. Although conventional roof-top-anchored window washing is effective, it is not always practical or cost efficient for single-unit needs, and improvement is needed.